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<H1>?X #= ?Y</H1>
X is equal to Y.


<DL>
<DT><EM>?X</EM></DT>
<DD>A linear term.
</DD>
<DT><EM>?Y</EM></DT>
<DD>A linear term.
</DD>
</DL>
<H2>Description</H2>
   This constraints states that the two linear terms are equal.  It is
   activated whenever the maximum or minimum of a domain variable is
   updated that might require updating other domains.  When propagating
   domain updates, the system takes into account only maximum and minimum
   values of the whole domain and makes sure that these values are
   consistent with those of other domain variables.

<P>
   If one of the arguments is a non-linear polynomial, this predicate
   delays until it becomes linear.

<P>

<H3>Fail Conditions</H3>
   Fails if the two linear terms have a different value.


<H3>Resatisfiable</H3>
   No.
<H2>See Also</H2>
<A HREF="../../lib/fd/NN-2.html">:: / 2</A>, <A HREF="../../lib/fd/HNN-2.html">#:: / 2</A>, <A HREF="../../lib/fd/HH-2.html">## / 2</A>
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